Conventional sealant materials are used with a variety of applications that require moldability and resistance to moisture and weathering. Generally, sealant materials may be formed by curing a mixture of siloxane-based polymers in the presence of a catalyst. The pre-cured mixtures are generally flowable, and may be poured into molds to create pre-formed sealant materials. Alternatively, the pre-cured mixtures may be poured directly into cavities of intended structures to create sealant materials that conform to the individual dimensions of the structures.
After curing, solidified sealant materials with varying degrees of elasticity may be obtained. Elasticity of the cured sealant materials depends upon a variety of factors, such as types and concentrations of siloxane-based polymers and additives, and the extent of the cross-linking. Typically, sealant materials exhibit adequate levels of elasticity to, at least initially, provide seals against moisture. However, it is known that such existing sealant materials exhibit poor mechanical properties (i.e., low tensile strength and elongation at break) that limits the use of the sealant materials in compressive environments. This may be overcome by adding silica fillers, such as fumed silica, to the sealant materials prior to curing. Upon curing, the fillers have been found to improve the mechanical properties of sealant materials.